If by 'sanctions' you mean 'cruise missiles', then yes, there will be many sanctions

if not military action

if? IF?! There would definitely be military action.

However, fallout is really overrated. If it's an airburst, fallout is really minimal. Even with a groundburst, the radiation levels will not be acutely dangerious even 24 hours after the detonation. The real danger from fallout is if there is a lot of it due to many nukes going off. North Korea is unlikely to have even double-digit nuclear weapons in stock.

Besides, the size of nukes NK has, the effects would be minimal outside of a mile or two. Nukes are powerful but they aren't anime-level powerful. NK nukes Seoul, sure millions are probably dying, but the rest of South Korea will notice the political and economic fallout far more than the radioactive fallout.

What will really happen is we will find out how much of a paper tiger the North Korean military is (hint, tissue paper) and how much China wants to back NK during an invasion (hint, about as much as you want a root canal).

Destroying what little infrastructure and stable population the country has will just mean more cleanup once the regime falls. This is one of the reasons that North Korea knows it can make these credible threats though everyone is united against them. It's the kind of fallout that no one in the region wants, especially China.

North Korea's status as the black hole of the region is just the kind of political instability that the Chinese regime fears.

Right. If they did then the resulting force against the country would be incredible. The regime would also likely level its own cities as they were taken by the allied forces, thus creating a larger toll on the state for after the regime is removed.

This is one of the greatest reasons why no one has invaded North Korea as it is safer and better for the North Korean citizens in the long run to let the regime decay.

Yeah, I see Obama doing this given the 37,000 US troops stationed inside South Korea that North Korea just nuked. Between US/Japan/South Korea (nevermind the fact that at this point even Russia would probably decide to provide support, and China would stand back and allow all this to happen) we would decimate their military in a few days. North Korea has a lot of troops, but not the kind of advanced technology that the nations who would bomb it do.

Exactly this. It would be like 9/11 squared - the idea that we would not go after NK is as ridiculous as the idea of us not going after the Taliban. (Ignoring that GWB demoted OBL from primary target at some point)

The US has only a cease fire agreement with North Korea not a peace treaty. While this is a bit of bureaucratic dancing the reality exists that any significant aggression by the DPRK would result in a large scale retaliation by the US and South Korea without the need for the UN security councils okay

Make no mistake about the willingness of the president to engage militarily on the peninsula if the DPRK does something as stupid a using a nuclear weapon. The Obama administration is very willing and interested in blowing shit up and all the rhetoric of him being some spineless hippie wing nut is naive to the point of stupidity.

There is also a possibility that China may invade North Korea if a nuclear event occurred simply so they might annex a buffer zone against South Korea and the US forces stationed there.

The Chinese army has little to no patience when it comes to wars in their backyard and has already threatened India and Pakistan about the tensions over Kashmir. If the Chinese are willing to wager war with a mass power like India over a neighbors squabbles then the possibility of steam rolling North Korea is very high given the loss of the security buffer North Korea gives China in its current state.

SK is a very important strategic partner of USA. We don't see anything from NATO countries yet, because NK has not done anything yet. NATO will retaliate the moment 20+ years of the ceasefire is ended by NK.

I found it kinda funny that, when asked for the political implications, everyone just said "duh the USA would destroy them." That's not political, that's militaristic.

The political implications would most likely be a huge blowback against China, for supporting the rogue state for so long, and President Obama. Now, I'm not saying it would necessarily be Obama's fault if the North nuked the South but the reaction would be huge against him and his state department. Republicans and probably most democrats would lie the blame at his door, for letting the North get away with it, as well as for a talking points example: "never putting his foot down with the rogue state."

Clausewitz famously said "War is the continuation of politics by other means". I don't think you can reasonably separate the political response ("We should invade") from the military response ("Hey, we're invading").

Fair, but based off general responses it seems that there's no agreement on what military action would be. Furthermore, I think that our reaction would define how we view our commander in chief afterwards.

Thanks for the comment. I think the fault lies with all the presidents since the Korean war for not spending more time to alleviate some of the tensions over there, and I agree that a lot of blame will be dumped on whomever is in office, I just don't see a bright side to this whole situation.

I don't know, it's not for lack of trying on the part of the US and international allies. The United States spent over 1 billion dollars from 95-08 on food and energy aid, and was prepared to make further food shipments to North Korea in the spring of 2009, that is, until Pyongyang launched a missile in direct violation of agreements it had with the UN.

Almost certainly, North Korea would fall quickly to a combination of US, SK, Chinese and other forces in the area. China protecting North Korea after such an act would be highly unlikely. The only question would be if it would take days or months and how active China would be in providing military support. Later, how North Korea would be split up between China and South Korea could take years and would be the focus of international politics between China and the US.

The interesting politics would be focused around Iran.

By NK 'going nuclear' there would be huge public support for taking out Iran now rather than later.

My guess is that the US would seize the opportunity and Iran would quickly capitulate, especially if North Korea fell quickly. Iran would agree to have their nuclear facilities dismantled and trade between Iran and the west would once again resume with the current Iranian regime staying in power. If this were to happen, then the people of Iran would be the biggest winner, after economic sanctions are lifted.

If Iran refused to give in on the nuclear issue, then it's likely that tensions would rise to the point where US/Isreal would find an excuse for a pre-emptive attack.

If the NK and Iranian governments were somehow able to resist (Maybe some weird nuclear standoff?) then coalitions would begin to form and the history books would probably call the incident WWIII. That almost certainly isn't going to happen though. But then again, NK attacking with nukes is almost certainly not going to happen either. :)

After the dust settled China, Russia, EU, US, Iran, Korea would all be more active trading partners, and the world would take one step closer into integrating into a truly one world economy.

No one would win in a Korean theater of war, current best estimate is that if NK struck first, it would do so with everything it has at Seoul and other population centers: at worst 40% of SK's civilian population would be dead inside of the first week.

Casualties for US/SK military personal would also begin to sky rocket after the first week as JLIST suit's failed or ran out ( nevermind there's a lot of questions about their integrity due to manufacturer defects ). Hopefully US forces could retreat far enough south to avoid the main brunt of artillery attacks.

Finally, US policy response to any use of WMD's against US forces is an immediate nuclear response which would decimate what little civilian population is still in North Korea ( it's assumed a lot of them would take the opportunity to flee into China ).

It's doubtful that China would directly get involved at this point because the USA still have China beat for nuclear capabilities and both countries are heavily co-dependant on each in a resources for manufacturing trade.

At the end of the month, it's likely that the Korean peninsula would have to be evacuated and become a tomb.

NOTE: GlobalSecurity.org give's you a handful of chances to read its content before it starts throwing up a pay-gate.

Update: A lot of people like to dismiss NK's rhetoric but it's probably better to view NK's foreign policy as being equivalent to a fat man in a crowded room who's got a suicide belt on and uses the threat of blowing himself(and everyone around him) to get concessions. This strategy has increasingly become less effective, forcing the DPRK to be more creative ( eg. selling it's civilians as slave labor in China, selling weapon technology to Iran or whoever else is buying ) but with diminishing returns. It's unlikely the DPRK civilians would revolt and external impressions is that the governing council is like a late stage chess game ( every piece is covered ) so unlikely a coup would be successful. So DPRK could still go through with starting a war as one last desperate suicidal attempt to keep itself going.

Update 2: Political/economic fallout if played out above, would be almost unfathomable. Samsung is a Korean company and they'd likely cease to exist, same goes for the hundreds of other high-tech companies originating in SK. Additionally their would probably be extensive blame at China's lack of involvement in preventing such an act... how that plays out is beyond my knowledge ( ex-USAF that works as an engineer now ) but growing opinion is that China has tapped out it's cheap labor pools and would experience serious economic harm due to consumer backlash. Whatever Korean refugees exist would probably have very little political capital in their home's but I could easily see a replication of the holocaust remembrance movement but much quicker to be adopted as there's no equivalent anti-semitic opinions toward's Koreans.

It's unlikely that Obama would suffer any major damage as President Obama generally listens to his joint chief's and military branch secretaries. Only question would be if he actually pulls the trigger on nuclear weapons or not, if he didn't it would have serious security issues for the USA and upset almost 50 years of stated foreign policy.

I can honestly only speculate, but I just don't see China opening their borders to a flood of poor and uneducated people. America wouldn't be indiscriminately bombing civilians (we may nuke the heck out of some military and industrial areas in or near cities, though) so I don't think they would feel obligated to allow them into their country.

Either that or fight to get NK absorbed back into SK which would finally reunify Korea after almost 70 years. Can you imagine the political capital and historical fame of being the person that reunified two of the most bitter national rivals in modernity? I don't think anyone would shy away from that opportunity.

I can honestly only speculate, but I just don't see China opening their borders to a flood of poor and uneducated people. America wouldn't be indiscriminately bombing civilians (we may nuke the heck out of some military and industrial areas in or near cities, though) so I don't think they would feel obligated to allow them into their country.

I see the Chinese as likely to welcome them into controlled refugee camps, with the intention of restoring them to the Korean peninsula after the fighting is done; China won't want to oppose the US in a military conflict, and they won't want to appear callous or vindictive against civilian neighbors in wartime.

What they'll do for sure is help resettle the refugees, and in doing so, guide the re-establishing social order to be very pro-China. I could see a future un-unified Korea after the defeat of the DPRK, still divided north and south, but more peaceful overall.

China gains a lot from the North Korean buffer zone, and I think that if such a scenario played out, they would take steps to ensure that their international reputation is improved and the buffer zone is preserved.

Can you elaborate or point me towards such policy of stated nuclear escalation that, according to you, is US doctrine if an enemy uses a nuclear bomb. And what "issues" in the realm of serious security ones would arise if the US in fact did not retaliate with a nuclear bomb? Seems like if China has a dog in this fight, out right blind adherence to 50 year old nuclear policy might just be dumb.

tl;dr While US foreign policy in response to WMD has never flat out said "If You use WMD's, we will nuke you into oblivion" but instead the language has always been that there would be an “overwhelming and devastating” response. It's unknown if the USA could take on a second theater of war even with the withdrawals in Afghanistan. So as you brought up, yes the CINC could decide not to use nuclear weapons but it's unlikely for both political and historical reasons that they would opt out.

Also you bring up a good point, regarding China's position towards a Korean war. This is theoretical and some what logical ( so it could be completely wrong when put to reality ) but China could actually spark a Korean war. If DPRK decides to continue with nuclear tests and or long range missile technology, it's likely that China would have to withdraw it's lifeline support to DPRK. This would then cause the DPRK to have to decide whether to implode or suicide and it's likely that it would have very little time to decide.

Last point, everyone in the world knows that the USA has the largest stockpile of nuclear weapon's positioned strategically around the world ( thanks to ICBM's, USAF PRP capable facilities, and deployed submarines). In the document linked above, they briefly theorize that Iraq held off using any remaining chemical weapons specifically because of the threat of nuclear weapons. USA's nuclear stockpile has been ten fold more effective in not using them but reminding the planet that it has them.

It's unknown if the USA could take on a second theater of war even with the withdrawals in Afghanistan.

Let's be honest here, if the North Koreans pop a nuke over a South Korean city...it's going to be a South Korean army show augmented by American forces. It's very likely the South Koreans would be reaching the Yalu before anything heavier than the Marines in Okinawa and the 82nd Could be flown in.

I'm largely assuming that nukes mwould not be used in retaliation. If "only" one is used by the North Koreans, there'll be cause for pause in American leadership circles. I actually think we'd be tempted to go exclusively conventional unless the South Koreans demand Pyongyang in revenge.

"At the onset of hostilities, North Korean Forces will seek to suppress Allied counter air operations. Scud-B and -C Missiles, with persistent Nerve Agent in the warheads, would be launched against airbases such as Kimpo, Osan and Taegu. Command, control, and communications centers, and logistics depots are also likely chemical targets." http://www.globalsecurity.org/wmd/world/dprk/cw.htm

Also Col. Conley's white paper pointed out that nuclear weapon use would have to be proportionally equal be legal. Even one barrage of low-intensity chemical weapon's would be enough to cause serious loss of life and casualties to a large swath of south Korean civilians. Any nuclear response would likely be focused entirely on the DMZ and artillery positions north of it.

The US, what's left of the South Korean army, and probably Russia and China would collectively stomp North Korea out of existence very quickly. Followed by political wrangling between the US and China about who gets to install a new puppet government. Probably not too dissimilar from how the US and Russia handled Germany after World War II.

In regards to Russia, this isnt the cold war anymore; Why would they have any reason to get involved in Korea? China, on the other hand, is more plausible. That said, the last thing China wants is confrontation with us at this point so I'd be very surprised if they got involved. What is more likely, as I previously mentioned, is that they would secure an agreement from us for complete (or nearly complete) military withdrawal from the peninsula in return for complete ROK control of Korea. Obviously that wouldn't mean we destroy the country and leave the next day but it is the long term solution.

If I were china I would freak the fuck out. Russia probably not, but China is an NK neighbor. They take on huge risks by not getting involved in stopping the kind of crazy that would be involved in NK nuking SK.

I doubt China or Russia would bother to intervene in the 2 weeks it took us to conventional bomb them into obscurity. Afterwards, the North would undoubtedly be turned over to Southern authority, likely in return for U.S. withdrawal. two other points: 1. if push did come to shove, Seoul is FUCKED. It is within range of artillery on the boarder that would tear it to pieces in the 48 hours before we got our shit together. 2. NK would nuke Japan before SK I believe.

Afterwards, the North would undoubtedly be turned over to Southern authority, likely in return for U.S. withdrawal.

The US would stay as peacekeepers, probably along with China and Russia. Too much animosity between North and South, plus South Korea would be busy rebuilding its own country and not have means to rebuild the north.

if push did come to shove, Seoul is FUCKED. It is within range of artillery on the boarder that would tear it to pieces in the 48 hours before we got our shit together.

North Korean artillery capable of reaching Seoul would be destroyed in far less than 48 hours just by personnel we have on the ground and the South Korean military. Seoul would still take a ton of damage, though.

NK would nuke Japan before SK I believe.

North Korea would have better luck delivering a nuclear warhead via slingshot than using its current missile systems.

South Korea would have enough problems rebuilding its own country, let alone North Korea and dealing with millions of starving refugees. The US and China would have to take over North Korea for a few years minimum before any reunification could be considered.

China would get very nervous having a US-backed country right on its border. They like the existing arrangement with North Korea serving as a buffer.

Well the US policy of deterring nuclear weapons relies on the threat that if you attack the US or their allies with a nuke, you can expect a proportionate response. I'd bet if anyone used a nuke the US's gloves would come off to ensure they don't get a second shot off and to prove that this policy isn't purely bluster.

This for sure. In addition, the North Korean army is so well dug in that, so I've read, about a third of the army would survive a nuclear carpet bombing and continue to fight. So simple conventional attack would probably be insufficient to defeat them.

The united states is treaty bound to defend south korea if attacked, that doesn't mean we have to set up bases in the rubble, but it does mean that attacking south korea is an act of war against the united states.

North Korea will not nuke South Korea. If they nuke anyone (big if) it would be Japan which represents imperialism in the region both in the past (WWII was pretty terrible to Koreans and Kim Ill Sung was a resistance fighter against the Japs) and in the present (America).

Obviously there would be sanctions if not military action, but wouldn't it be dangerous to send troops into a volatile situation like nuclear fallout?

When the shit hits the fan, there is no "situation" left. At such a moment, it all comes down to a matter of survival - i.e -who has more nukes and whose nuke strikes first, without being intercepted.

Realistically speaking though, North Korea would be asking for a death wish if it tried anything funny. USA even today has more nukes than all the nuclear armed countries in the world combined. North Korea would be fucked, even with China and Russia's support.

In addition to the 4,500 in the military stockpile, 4,000 retired warheads are estimated to be awaiting dismantlement. Details are scarce, but we estimate that Russia is dismantling approximately 1,000 retired warheads per year.

meaning not part of the chart, the US has about the same amount being dismantled each year....Gotta remember the USSR used to have 45,000, and the US used to have 38,000, read "h" it says the same thing except for the USA

Both countries have been scaling back since 1991

The numbers in the chart are the best guesses for operational nuclear war heads

The United States military (and I'm assuming they'd be involved because SK is our ally) is well aware of the dangers posed by fallout and has been preparing for the possibility of total nuclear war since the end of World War II. I'm sure they have a plan for conducting action in such an area while minimizing exposure to radiation. It probably involves a lot of air to surface action combined with waiting for the enemy to succumb to radiation poisoning.